The Kitten Programming Language

Kitten is a statically typed, stack-based functional programming language designed for simplicity, speed, and safety. This is an in-progress implementation of that language, including:

• An interactive console for testing code

• An interpreter

• A native-code compiler producing static executables (incomplete)

Contributing

I need help to make Kitten a reality! If you’re interested in helping in any way, you’re more than welcome, even if you’re not experienced with Haskell or compiler development. You can look at the project for the initial release to see what I’m working on, and check out the contribution guidelines for suggestions on how you can help.

Resources

• Browse some examples to get a feel for the language

• Join the chat room to ask questions

• Skim a quick intro on the official site

• Read the most recent updates to the ebook

• Read my article introducing some interesting things about concatenative programming, Why Concatenative Programming Matters

• Watch my lecture describing the theory, history, and implementation techniques of the paradigm, Concatenative Programming: From Ivory to Metal

Building and Installing

If you’re building the compiler just to try it out or work on it, you can follow the preferred build method of using Stack:

git clone https://github.com/evincarofautumn/kitten.git
cd kitten
stack setup  # only necessary on first build
stack build

stack exec kitten
stack exec kitten -- <flags>

However, if you want to install Kitten in a standard location outside the build directory, due to a deficiency in Stack’s support for Cabal’s data-files feature, it is not recommended to use stack install to install a copy of the executable, because this will not install the common vocabulary common.ktn containing Kitten’s standard library.

There are two workarounds. One is to forgo Stack, and build and install Kitten using Cabal directly:

cabal sandbox init
cabal install --only-dependencies
cabal install --prefix="$HOME/.local"

This will correctly install the common vocab so that Kitten can find it. The preferred install location for Kitten is ~/.local on Unix-like systems (so the executable resides at ~/.local/bin/kitten) or %APPDATA%\local on Windows (resp. %APPDATA%\local\bin\kitten.exe).

The other option is to manually copy common.ktn to the install directory:

stack install
cp common.ktn ~/.local/bin/

It’s also recommended to add the install directory (~/.local/bin or %APPDATA\local\bin) to your PATH so that you can invoke kitten directly without a path prefix.

These are the only files installed by Kitten, so to uninstall it, you only need to delete the compiler and common vocab from the install directory.

Miscellany

Kitten is distributed under the terms of the MIT license. Contributors should agree to abide by the code of conduct.